Control means for operating in timed relation the work clamp and the needle of a sewing machine of the tacker type



United States Patent [72] Inventor Arthur C. Wokeck 1 2 Lindewoods Road, Norwalk, Connecticut 06851 211 AppLNo. 761,144 1 1 22 Filed Sept. 20, 1968 7 v 1 Continuation-impart of Ser. No.'615,1 )4l, 3 Feb 3, 196?,ahandond. f [45] Patented Dec.8, 1970 [s41 CONTROL MEANS FOR OPERATING IN 11 11;

RELATION THE WORK CLAMPANI) T1111 v NEEDLE or A SEWlNG MACliiNE QF r1111 2 ,764,112 9/1956 Happe....

3,245,369 4/1966 Myska 112/67 FOREIGN PATENTS 597,893 12/1938 GreatBritain ..l.l2/219(F.O.)UX

Rrirr ory EJramin er-Y-H. Hampton Hunter A ttar ney lohnw. Hoag ABSTRACT: For raising the work clamp and closing the 1 clutch of the llnleedle driving means of a sewing machine of the tackertype, a pivoted operating arm is provided and its ends,

which act through rods connected to work clamp and clutch 1 actuating members 1 respectively, are alternately raised and lowered by means of a singlefluicl cylinderzthe piston of which is alternately raised and lowered by fluid pressure alternately applied on opposite sides of the piston through two fluid,'valve controlled conduits. The valve means permit fluid to be exlhaust'ed from, as well as supplied to, opposite sides of the pistonin timed relation, one of the valve means being respon- 1 siye to closing and opening of the clutch for synchronizing the operation of the fluid system with the duration of a sewing operation.

PATENTED 050 8.910 3.545388 sum 2 0r 2 tinuationin-part of pending application SER. NO. 615,041,

filed Feb. 3, 1967, now abandoned.

More specifically it relates to control means acting with known work clamp and needle drive actuating means, which may be of the kind employed in existing, conventional tackers, to actuate a sewing operation, or a series of sewing operations, the nature and extent of which are controlled by means provided in conventional tackers (usually cam control means) and which form no part of this invention.

The control provided causes the known work clamp of the tacker to be moved toward and away from a work support surface, in timed relation to the operation of a reciprocable needle and needle. More exactly, in one working (inclined) position it causes a downly biased work clamp to, be raised while letting needle drive clutch means he returned to open position by its biasing means, or leaving the needle drive clutch means held disengaged by its biasing means, and in another .(oppositely inclined) position it causes the needle drive clutch means to be engaged, overcoming its disengaging biasing means while letting the work clamp biasing means return the work clamp to lowered, working position. This is accomplished by a single pivoted operating arm the ends of which positively engage work clamp and needle actuating rods when the said ends are alternately moved up, in one direction, and are slidingly related to the said rods when said arm ends are alternately moved down in the opposite direction. The arm is tilted by a single fluid cylinder the piston of which is oppositely actuated by fluidfrom two valve controlled fluid conduits. Prior art control means are complicated and expensive because of the multiplicity of parts employed. And prior art control means employing separated foot pedals which must be depressed by an operator one at a time, and in proper sequence, are unsatisfactory because of the difficulty in obtaining or training operators with the necessary sense of timing, and because of the costly damage which can result from human failureas when an operator presses on both foot pedals at the same time. The present invention overcomes both of these difficulties because by the method and apparatus disclosed herein it is impossible to raise the work clamp and to start the needle drive except in sequence, and the simple structure effects an important economy.

Perhaps the most pertinent prior art is US. PAT. No. 3,298,34l, Jan. 17, 1967. That patent discloses a sewing machine control for raising and lowering a work presser foot and for opening and closing theclutch of needle reciprocating means, which employs two air cylinders the pistons of which are moved in only one direction by pneumatic means and are moved in the opposite direction by spring biasing means the spring means of one cylinder being used to hold the presser foot in its operative position and pneumatic means being used in the other cylinder to close the clutch). That patent disclosed a fluid interlock to protect the machine in the event that air pressure should fail in either air line. The interlock system complicates and increases the cost of the pneumatic system and it will be noted that in the system disclosed herein no such interlock system is needed for applicants pivoted operating arm insures that the work clamp can only be raised when the clutch members are disengaged and that the clutch members cannot be closed unless the work clamp is lowered. Since the ends of the operating arm can only be lowered in sequence the danger that the sewing machine could be damaged either by air failure or improper operation of the control sequence is eliminated.

Principal objects of the invention are to provide simple, dependable and relatively inexpensive control means by which the work clamp raising, and the needle drive clutch closing can only be performed in sequence thus eliminating the damage and loss of time caused by mamming, resulting from human failure or failure of a power line. Another object of the invention is to make it possible for an operator to do more workwhile suffering less strain.

The invention will be best understood by reading the following description in connection with the drawings in which,

FIG. 1 is a schematic view partly in perspective of a system embodying the invention showing the work clamp raised and the needle driving clutch open.

FIG. 2 is a view similar to FIG. 1 but showing the disposition of the parts when the work clamp is down and the clutch closed.

In the embodiment of the invention illustrated herein, in the upper part of the drawings the following parts of a conventional sewing machine of the tacker type are shown:

A work clamp which is biased downwardly by the spring means 11 is positioned for movement toward and away from a support surface 12 on which a garment or other fabric is supported during a sewing operation, and the work clamp actuated lever 14 which is pivoted intermediate its ends on the pivot support 16, and i is pivotedly connected at 18 to the upper end of the work clamp. Disposed adjacent to the work clamp 10 and above the support surface 12 is the needle 20 and itssupporting clamp 22, which are reciprocated, to per form a sewing operation on a garment or other fabric placed at the support surface 12 below work clamp 10, by the drive means indicated generally by numeral 24 and by its clutch means shown herein as comprising the stationary clutch member 26, the belt 28 which may be driven by the motor 30, and the movable clutch member 32 which is associated in any suitable way with the short arm of a bellcrank 34 supported on the support pivot 36, the long arm 38 of the bellcrank being biased upwardly by the spring means 39.

The control means which, comprises this invention and which is provided for cooperation with spring 11 to actuate the work clamp 10, and to cooperate with the spring 39 for closing and opening of the needle drive clutch member 32 in timed relation to the raising and lowering of the work clamp 10, comprises, theoperating arm 40 which is pivoted intermediate its ends on a support pivot 42. The left hand end 40a,

when the end 40a of operating arm 40 moves downwardly contacts the enlarged end 46 of the operating rod 44 and pulls rod 44 downwardly. Since the upper end of rod 44 is pivotedly connected at 48 to the end of lever 14 which is opposite the pivot 16 from the connection between the lever 14 and the work clamp 10, downward movement of rod 44 serves to elevate clamp 10 against the force of spring 11.

The end 40b of the-operating arm 40, which is the right hand end of the arm as viewed by the reader, is similarly provided with the eye 50, which serves as a guide for the operating rod 52, which extends through it, and also as an abutment member which strikes the enlarged lower end 54 of arm 52 when the right hand end 4017 of operating arm 40 is swung downwardly. When this occurs the operating rod 52 is pulled down, and since its upper end is pivotedly connected by pivot 56 to one end of the long arm of the bellcrank 34 the said long arm is pulled downwardly against the force of spring 39 thus moving clutch member 32 into clutch. closing position, and actuating the needle drive. i

From the above description it will be understood that when the left hand end of the operating arm 40 moves downwardly from a neutral or horizontal position it will strikeenlarged end 46 of the operating arm 44 and pull arm 44 down, thus raising the work clamp 10, and that while the end 40a of operating arm 40 is down the end 40b must necessarily be up and in that position will be only slidingly related to the operating arm 52 and will not in any way interfere with the action of spring 39 in opening the needle drive clutch and holding it in open position. 1

It will be understood that similarly, when the right-hand end 40b of operating arm 40 moves downwardly, below neutral or horizontal position, it will strike the enlarged end 54 of operating rod 52 and will pull rod 52 downwardly, overcoming the force of spring 39 thus engaging the clutch, and that while end 40b is down the end 40a must necessarily be elevated and in that position will be only slidingly related to the operating arm 44 and will not interfere with the action of spring 11 in lowering clamp and holding it in lowered position. Operating arm 40 is alternately swung counterclockwise and clockwise on its support pivot 42 by the reciprocation of the piston rod 64, the upper end of which is connected to the rod 40 by means of the clevis 66 and the pivot pin 68 therein. The lower end of rod 64 is connected to the piston 62, the position of which within fluid cylinder 60 is determined by conduit means leading to the upper and lower ends of said cylinder respectively, on opposite sides of the piston 62 and through which air or other operating fluid may alternately be supplied and ex hausted by the operation of the valve means disposed within said two air conduits.

As shown herein two air conduits 74 and 94 are connected by a T-fitting 70 with a conduit 72 leading from a source of supply of air under pressure and controlled by the on-off valve 73. Conduit 74 comprises a portion 74a leading from the source of supply conduit 72 to a valve 76 which is normally open" and in communication with conduit portion 74b, but which when closed" cuts off air from 740 and puts conduit part 74b in communication with the exhaust port 78. Conduit 74b is connected at its other end to valve 81 which is also normally open" and connects conduit part 74b to the conduit part 74c but has the exhaust port 82 and when closed connects conduit 740 to the exhaust port. The other end of conduit 740 communicates with cylinder 60 below the piston 62.

Instead of being controlled by a plunger, valve 81 is controlled by a pivoted arm 84 the free end of which extends under the lower end of operating rod 52 in a position such that when rod 52 is moved downwardly by the right-hand end of operating arm 40 the lower end of rod 52 will contact and depress arm 84 thus closing the valve with respect to conduit 74b but opening it for evacuation of air from below the piston in cylinder 60 through conduit 74c and the exhaust port 82, as

. will be more fully described in the following description of the system. 1

The term valve is used herein to include three way air microswitches of the kind commercially available from Mead Specialties Co., Inc. of4 l 44 North Knox Avenue, Chicago 41,

' Illinois whichare preferably employed.

Conduit 94a is coupled to the source of the air under pressure when valve 73 is open. Conduit 94a is connected with the n.c. valve 96 which in its normally closed position communicates between conduit 94b and the exhaust port 99, and when open" communicates between conduit portion 940 and 94b. The other end of conduit 94b communicates with the upper end of cylinder 60 above the piston 62.

As indicated in the drawings, the valve members 76 and 96 are preferably disposed side by side and are operated by a single foot pedal 100 which is pivoted at 102 to the base member 104. The plunger 80 is shown extending above the plunger 98 so that as pedal 100 is pushed down one-half way it will depress plunger 80 and close normally open valve 76 without affecting valve 96, and when the pedal 100 is depressed to its second position it will operate plunger 98 and open normally closed valve 96 without affecting valve 76.

It will be understood that with valve 96 in its normally closed position conduit 94b will communicate with exhaust port 99, and that when valve 76 is moved to closed position from its normally open position, conduit 74b will communicate with exhaust port 78, and that when valve 81 is moved to closed position from its normally open position conduit 74c will be connected with the exhaust port 82.

The operation of the apparatus is as follows:

1. Open supply valve 73. This allows air to flow from the source of air supply through conduit 72, and valve 73 and the T connection 70, into both air conduits 74 and 94. Since the three-way air microswitch 96 is closed and switches 76 and 81 are open air will flow into the lower end of cylinder 60, causing piston 62 to be lifted from neutral position, thus swinging operating arm 40 from its neutral, substantially horizontal, position to an inclined position with the eye 43 at its left end 40a moving down into engagement with the enlarged lower end 46 of operating rod 44 and pulling rod 44 down and swinging clamp actuating lever 14 on its pivot 16 and raising work clamp 10 above the work receiving surface 12 of the sewing machine in preparation for the operator to place on said surface the material, garment or other fabric on which a sewing operation is to be performed. Raising of the right-hand end 40b of operating arm 40 has no effect as the eye 50 moves up along rod 52.

2. The operator presses pedal 100 half way down, and, because the operating plunger of normally open three-way air microswitch 76 extends above the operating plunger 98 of normally closed three-way air microswitch 96, plunger 80 is first depressed and this action closes valve 76 relative to the air supply source but opens communication between the lower end of cylinder 60 and exhaust port 78 of valve 76 and allows a portion of the air below the piston 62 in cylinder 60 to be exhausted through the third part 740 of the first conduit, valve 81 which is still open, and through conduit 74b and the exhaust port 78 of valve 76, allowing piston 62 to return to middle or neutral position aided by spring 11. When piston 62 moves down the piston rod 64 swings arm 40 back to neutral substantially horizontal, position, and, the down pull on operating arm 44 being thus relieved, the clamp biasing means 11 lowers clamp 10 onto the work piece which has been inserted on support surface 12 below the needle 20.

3. The operator now presses the pedal all the way down. This does not affect switch 76 which remains closed, but n.c. switch 96 is opened allowing air from the source to flow into the top of cylinder 60, forcing the piston 62 downwardly from its neutral middle position and thus causing piston rod 64 to swing operating arm 40 clockwise, lowering its end 40b and causing the eye 50 to engage the enlarged end 54 of operating rod 52 and pulling rod 52 down, thus swinging bellcrank 34 on its pivot 36 against the pull of spring 39, and closing clutch 32- 26 which actuates the sewing machine mechanism 24 for reciprocating the needle 20 and its supporting clamp 22. The down movement of the end 40b of the operating arm and of rod 52 causes the lower end 54 of rod 52 to contact and depress the operating arm 84 of normally open three-way air microswitch 80 thus closing the switch with respect to the second part 74b of the first conduit 74 but opening the switch for exhausting air from below the piston 62 in cylinder 60 through the third part 740 of the first conduit and from exhaust port 82 of air switch 81.

Closing of the clutch locks the sewing machine in operating condition until the sewing operation is completed and bellcrank 34 and operating rod 52 remain in down position to the end of the sewing operation, when means, not shown, allows spring 39 to open the clutch. The particular sewing operation performed is determined by means within the sewing machine, usually cam means. When the sewing operation is completed the sewing machine unlocks and spring 39 urges the bellcrank to swing and open the clutch. The operator anticipates the end of the sewing operation and relieves the downpull on operating rod 52 before the end of the sewing operation to allow the biasing means 39 to open the clutch when the sewing operation is concluded.

4. In preparation for the end of the sewing operation the operator removes his foot from pedal thus reopening n.o. switch 76 and closing n.c. switch 96 relative to by of air supply. Air is then exhausted from above the piston 62 through conduit part 94b and exhaust port 99 of valve 96. As valve 81 is held closed until the end of the sewing operation by rod 52 conduit part 74c remains open to exhaust port 82 of valve 81 and the pneumatic system is neutralized and remains so until the sewing operation is over. This relieves rod 64 of any force tending to move it, but operating arm 40 remains inclined with end 40b down. When the opening of the clutch (by sewing machine means not shown and by biasing means 84 of valve 81, valve 81 then resumes its normally open condiquickly and is a single continuous operation by an experienced operator.

The clamp may be raised or lowered any time prior to clos- 1 ing the clutch, by engaging the switch 96 for repositioning of the work. i i

There has thus been provided a system by which the above mentioned objects are attained in a simple and practical way.

I claim:

1. In combination with a sewing machine of the cyclic type having a work clamp moveable between a nonoperative position, spaced from a work support surface on which the materialto be sewn is placed, and an operating position in which said clamp presses on the material on the work support, a pivoted work clamp actuating lever, and means normally biasing the said lever to move the clamp from nonclamping to clamping position, areciprocable needle, driving means for reciprocating the needle including a clutch, pivoted bellcrank means for engaging and disengaging the clutch, means normally biasing the bellcrank for clutch disengaging movement, and control means for coacting with both of said biasing means for actuating said work clamp actuating lever and said bellcrank in timed relation, comprising, an actuating arm pivoted intermediate its ends, means for swinging said arm on its pivot to alternately raise and lower its ends, a pair of operating rods, the upper ends of which are connected to said lever and said bellcrank respectively on the far side of their pivots from the clamp and the clutch, means slidingly connecting the lower ends of said operating rods to the respective ends of said actuating arm so that the rods are slidingly related to the respec tive ends of the pivoted arm as said rods are moved upwardly by said biasing means, and so that the ends of the pivoted actuating arm, as they alternately move down, engage and pull down the operating rods respectively to swing the work clamp actuating lever and the bellcrank respectively to move the work clamp away from the work support when said actuating arm is pivoted in one direction and to close the clutch for driving the needle when said actuating arm is pivoted in the other direction, the means for swinging said actuating arm comprising a pneumatic system including a source of air supply, valve control means therefor, an air cylinder having a piston therein, and a piston rod which is connected to said pivoted arm on one sideof its pivot, a plurality of air conduits leading to opposite sides of the piston in said cylinder, valve means in said conduits for alternately supplying air to, and exhausting it from, opposite sides of the piston in said cylinder, valve control means for operating said valves, in timed relation, and ad-I ditional valve means in one of said air conduits coactive with one of said operating rodsto neutralize the pneumatic system upon release of the valve control means during a sewing operation thereby permitting the sewing machine to complete its sewing cycle. a i

2. The combination claimed in claim 1 in which the valve means comprises, three three-way air microswitchesin said conduits each adapted to be open or closed with respect to passing air in one direction, and to be open to exhaust air flowing from the opposite direction, two of said air switches being disposed in sequence in one of said air conduits, one of said two air switches having air flow controlling means therein connected to the operating rod which is connected to said bellcrank to neutralize the pneumatic system during a sewing operation.

3. The combination claimed in claim 1 in which the pneumatic means comprises, a first conduit for supplying air to, and exhausting air from, said cylinder below the piston therein, and a second conduit for supplying and exhausting air to and from said cylinder above the piston therein, said first conduit comprising a part leading from the source to a first three-way air microswitch,,a second part leading from said first three-way microswitch to a second three-way air microswitch, and a third part leading from saidsecond threeway air microswitch to said cylinder, said first and second three-way air microswitches each having an exhaust which is open when the switch is closed relative to said source of air supply, said first switch being normally open and having a control memberfor closing said switch relative to the source and opening the switch for exhaust of air from said second part and having anoperating arm for closing the switch relative to said second part and to exhaust air flowing to said switch from said cylinder through said third part, said second switch being disposed relative to the bellcrank operating rod so that said arm is disposed in the path of movement of said operating rod, for actuation by said rod at the end of its clutch closing movement to exhaust airfrom beneath the piston in said cylinder thereby neutralizing the pneumatic system during a sewing operation.

4. The combination claimed in claim 1 in which the addithird air switch is provided in the second conduit, said first and A third air switches each having actuating plungers disposed so that the switches are operable only in sequence, and unitary pedal means for operating the plungers of said first and third air switches. i t 

